Electronic modules which use a cover or lid need to be assembled in a matter that provides mechanical protection while addressing the dimensional, mechanical, thermal and in some cases electrical requirements of the assembly. During a traditional assembly of die onto organic laminates and subsequent adhesive lid attach to the laminate and die, significant stresses can be developed due to respective material thermal expansion mismatches that cause the laminate to warp. This complicates the placement of bottom side solder balls (where ball grid array (BGA) packages attach to cards) if the warpage is severe, since the balls will not sit on a common plane to reliably join to a planar card input/output (IO) array surface with solder. Similar planarity issues are encountered for modules which are joined to, for instance Land Grid Array (LGA) connectors which use compliant contacts such as springs to create electrical paths between the laminate surface and a surface such as a card, board or other electrical interface. The contacts may not all be fully engaged or forcefully mated to be reliable. This problem, referred to as a coplanarity issue, is magnified if the laminate is of low rigidity as is found with coreless laminates, as coreless laminates do not have the traditional thick glass fiber stiffening central core.
In addition to the coplanarity issue, a variety of other thermal and mechanical challenges exist in the fabrication of electronic modules. The warpage that results can have an adverse effect on the thermal interface material (TIM) that resides between the die and the underside of the lid. This TIM provides a physical thermal path for heat generated in the die to flow to the lid and from there be further removed by using heatsinks, coldplates, etc. to prevent overheating of the package and maintain electrical performance of the module. Therefore, it is desirable to have an improved electronic module and methods of fabrication that mitigates the aforementioned problems.